The present paper investigates the influence of the execution history on the precision of measurementbased execution time estimates for embedded software. A new approach to timing analysis is presented which was designed to overcome the problems of existing static and dynamic methods. By partitioning the analyzed programs into easily traceable segments and by precisely controlling run-time measurements with on-chip tracing facilities, the new method is able to preserve information about the execution context of measured execution times. After an adequate number of measurements have been taken, this information can be used to precisely estimate the Worst-Case Execution Time of a program without being overly pessimistic. Digital Object Identifier 10.4230/OASIcs.WCET.2010.64